This invention relates to .beta.-lactam antibiotics. In particular, it relates to intermediates useful in the preparation of 1-carba(dethia)carbacephalosporin antibiotics.
In contrast to the cephalosporin antibiotics, which are prepared semisynthetically, 1-carba(dethia)carbacephalosporins have thus far been obtained, for the most part, by totally synthetic methods. For example, Christensen et al., U.S. Pat. No. 4,226,866, describe a method for the preparation of 1-carba(dethia)carbacephalosporin antibiotics. Also, Evans et al., U.S. Pat. No 4,665,171, describe an asymmetric total synthesis of the amino-protected 3-hydroxy-1-carba(dethia)carbacephalosporin nucleus ester. Morin et al., U.S. Pat. No. 4,885,362, describe a semisynthetic method wherein utilizing azetidinone-2 intermediates in the preparation of 1-carba(dethia)carbacephalosporins. Because of the growing importance of 1-carba(dethia)carba-cephalosporins as therapeutic agents for the treatment of infectious diseases, intermediates and methods useful in the preparation thereof are of considerable value.